Francisco Alvarez exits with back spasms in potential Mets injury nightmare

MILWAUKEE — At a point when it felt like it couldn’t get any worse for the Mets , Francisco Alvarez slid into third base and could not get up.

Alvarez exited with back spasms in the top of the seventh of an ugly 8-4 loss to the Brewers at American Family Field on Friday.

On a night Francisco Lindor made his return from back discomfort, Alvarez’s back became a concern for a Mets club that could ill afford to lose the slugger in the last weekend of the season during a playoff chase.

After a base-running incident in which Alvarez said he felt “scared,” he stretched, got massaged and reported improvement.

“I feel way better,” said Alvarez, who had never experienced back spasms before. “Let’s see [Saturday] how it’s going to feel.”

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The Mets catcher reached first base on a walk, advanced to second on a wild pitch and dashed for third as Tyrone Taylor grounded out.

Alvarez said he felt his back tighten up just before sliding into the base feet first. He grabbed at his lower back, yelled and signaled to the dugout while grimacing.

Alvarez lay flat on his chest for about a minute and rose, with help, before needing assistance both to get off the field and get down the dugout steps.

“When he first came out, it didn’t look good,” said manager Carlos Mendoza, who added the club has catchers at camp in Port St. Lucie who could be added if needed. “For the past 30 minutes or so, he’s walking around, feeling definitely better.”

It was a rough development in a rough game in which the Mets — Alvarez included — did little right as they hunt for a wild-card spot.

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Luis Torrens pinch-ran (and was stranded) before remaining in the game at catcher.

If Alvarez has to miss time — a troubling notion with a maximum of four games left in the regular season — the light-hitting Torrens would be thrust into an everyday role.

Alvarez’s bat has come alive in the past two weeks, having launched five of his 11 home runs this season in the past 12 games, a stretch in which he has raised his OPS from .664 to .706.

He reached base in two of his three plate appearances Friday and should have reached a third time. Alvarez fought through a lengthy battle with Frankie Montas in the fourth inning with two outs and two men on base.

After fouling off four straight full-count offerings, Alvarez stared at a breaking ball that appeared to be below the zone.

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Home-plate umpire Ramon De Jesus ruled strike three, ending the frame, ending what would have been a bases-loaded opportunity for Tyrone Taylor and ending the night for Mendoza, who was ejected for a second time this year.

“He didn’t have a good game behind the plate,” Mendoza said of De Jesus, although he probably could have said the same about Alvarez.

The Mets were outplayed and outrun by the NL Central champion Brewers, who entered play second in the majors in stolen bases and were as aggressive as advertised.

The Brewers stole six bases — five off Alvarez and one off Torrens — including three by Brice Turang.

Three additional times, they advanced bases on a pair of wild pitches (by Sean Manaea and Danny Young) and a passed ball by Alvarez, which was his MLB-leading 10th of the season.

“We gotta quicken our time to the plate,” said Mendoza, placing the blame on the Mets’ staff. “That’s what they do as a team, and we knew that coming in. We have to make some adjustments and stop them from continuing to run like that.”

Torrens has been better at holding runners on base this season, though Alvarez’s bat is stronger.

“They took good jumps,” Alvarez said. “It’s tough when the runners can take good jumps.”

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